CVE-2021-47103
A flaw in the Linux kernel’s networking code can cause a use‑after‑free error when handling certain packets. The bug could let an attacker crash the system or potentially run code without needing any special privileges. It was discovered by automated testing and has been fixed in later kernel releases.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
Linux kernel 5.16 and earlier versions that have not applied the RCU fix for sk_rx_dst. Users running these kernels on any distribution are affected.
Real-world impact
An attacker could send crafted network packets to a vulnerable system, causing it to crash or, in the worst case, execute arbitrary code with kernel privileges.
Why this severity
The CVSS score of 9.8 reflects that the vulnerability gives an attacker full control over confidentiality, integrity, and availability, requires no special privileges, and can be triggered over the network.
What to do about it
- 01Upgrade to a Linux kernel version that includes the RCU fix for sk_rx_dst. 3. Reboot the system to load the new kernel.
NVD-referenced vendor advisory
Timeline
- Mar 4, 2024 · Mar 4, 2024PublishedDisclosed and added to the National Vulnerability Database.
- Aug 4, 2026 · 2d agoAdvisory updatedThe NVD record was last revised.
- Aug 5, 2026 · 19h agoOfficial fix availableA vendor patch or mitigation now exists — see the remediation steps above.
How it’s attacked
References & advisories
- git.kernel.org/stable/c/0249a4b8a554f2eb6a…exploitmailing listpatch
- git.kernel.org/stable/c/68c34ce11ef2332869…exploitmailing listpatch
- git.kernel.org/stable/c/75a578000ae5e511e5…exploitmailing listpatch
- git.kernel.org/stable/c/8f905c0e7354ef2613…exploitmailing listpatch
- git.kernel.org/stable/c/92e6e36ecd16808866…exploitmailing listpatch
- git.kernel.org/stable/c/c3bb4a7e8cbc984e1c…exploitmailing listpatch
- git.kernel.org/stable/c/f039b43cbaea5e0700…exploitmailing listpatch